Development of intensive technology for constructing low-rise building walls from ash-cement mix

Abstract

There is a great demand for low-rise construction in Uzbekistan. In this regard, it is necessary to continue research on the intensification of the technology of monolithic low-rise housing construction using primarily local waste from various industries. One of them is fly ash waste from the electric power industry. It is proposed to use fly ash as a filler in a cement-ash composition, and it is considered more affordable. The use of other industrial waste as fillers requires additional special processing such as drying and grinding. It was established that fly ash is more accessible for practical use. From the point of view of the structural theory of composite building materials, fly ash has a plasticizing ability, which in turn helps to reduce water consumption. It was established that it is appropriate to use mineral additives in combination with other additives in the preparation of concrete mixes with high workability and low cement consumption. To determine the strength properties, samples were prepared from an ash-cement mix with a water-cement ratio of 0.32, with a fly ash content of 85% of the total mass of the mix. The hardener additive (soda powder) was used at 1.5% by weight of the binder and activated in the mixers for 2 -4 minutes. The results of the study show that the additive accelerates the hardening process of the ash-cement mix by 80-90% at one day of age, due to activation, the strength increases by 11-22% for the mix with/without the additive, respectively. When the mix is activated, the particles are struck and the inert film is torn off from their surface and free access of water to the ash particles is ensured; this, in turn, leads to an increase in the number of hydrate formations and a deeper occurrence of hydration processes. We studied the effect of the sequence of loading components in a working mixer on strength indices. The strength of the mechanically activated mix with 80% fly ash content and 1.5% addition of soda powder, reached 18.5-19.5 MPa. An ash-cement mix for concreting monolithic low-rise buildings was developed.